Development of a Raman method to follow the evolution of coating thickness of pellets

Krisztina Nikowitz, Friederike Folttmann, Markus Wirges, Klaus Knop, Klára Pintye-Hódi, Géza Regdon, Peter Kleinebudde

Research output: Contribution to journalArticle

7 Citations (Scopus)


Context: Although several methods have been investigated to measure the film thickness of tablets and its correlation with the dissolution behavior, much fewer such investigations exist for pharmaceutical pellets. Objective: To study the possibility of measuring the film thickness and predicting the dissolution behavior of pellets produced in different fluid bed equipments with Raman spectroscopy. Materials and methods: Pyridoxine hydrochloride-layered pellets were produced and coated in two different Strea-1 equipments. Raman spectra were collected and analysed to set up a calibration model based on the film thickness data calculated from Camsizer analysis results. Dissolution tests were done according to Ph. Eur. standards. Results: Raman spectroscopy proved to be a good tool in the measurement of film thickness. Polymer weight gain showed a linear correlation with film thickness but was a poor predictor of dissolution results below a threshold value. Conclusion: The Raman spectroscopic measurement of a small sample can provide accurate data of the film thickness. The investigation suggests that a threshold value might exist for the film thickness above which it can be used to judge future dissolution results.

Original languageEnglish
Pages (from-to)1005-1010
Number of pages6
JournalDrug development and industrial pharmacy
Issue number8
Publication statusPublished - Aug 2014


  • Chemometric analysis
  • Dissolution
  • Film thickness
  • PCA
  • PLS
  • Pellet
  • Raman

ASJC Scopus subject areas

  • Pharmacology
  • Pharmaceutical Science
  • Drug Discovery
  • Organic Chemistry

Fingerprint Dive into the research topics of 'Development of a Raman method to follow the evolution of coating thickness of pellets'. Together they form a unique fingerprint.

  • Cite this